Electric switch



D. G. KlMBALL ELECTRIC swrfrcn Filed Apri; 13, 19:59

May 27, 1941,

2 Sheets-Sheet 1 l l` /dlll A Wnmmm y May 27, 1941. D. G. KIMBALL2,243,566

ELECTRIC SWITCH Filed April 13, 1939 2 Sheets-Sheet 2 NN HL2 N` PPL:

Inventor: Donald G. Kimball,

Patented May 27, 1941 2.243.568 l 4ELIMII'IIIJC SWITCH Donald G.Kimball, Stratford. Conn., aligner to General New York Electric Company,a corporation of Application April 13, 1939, Serial No. 267,567

- (ci. zoo-c) Sclalml.

'I'his invention relates to electric switches, andP more particularly toswitches for controlling electric heating systems, for example, electricranges.

The object of the invention is the provision of an improved constructionand arrangement in switches oi the type described of relatively fewparts, which are easily assembled and manufactured at low cost.

l'n the accompanying drawings Fig: l is a view of the front of theswitch with a portion of the casing removed to show the positioningmechanism:lig.2isaviewoftherearof theswitch with the closure plateremoved showing the interior of the switch; Fig. 3 is a sectional viewthrough the switch along the line 2-2 of Fig. l; Fig. 4 is another viewof the interior of the switch similar-tothe showingofFig.2buttakenalongtheline44ofiig.3;andligs.5to8,inclu sive. are diagrammatic showings ofthe switch connected to control a two-part heater' systemsuchasisusedonelectricranges.

Referring to the drawings the switch is provldedwithabasemember ilofinsulatingmaterial, such as a phenolic condensation product andfiller, formed on one side with a recess'ii extendingfrcmtherearface i2:asecondrecessilextendsfromthefrontiaceofthabase memberand thetwoiiandilareseparatedbyapartitionil. Therecessiiprovides ahousing formounting the switch mechanism while the recess I2 forms `a housing for apositioning mechanism.

comparhnents,asshownbyl'ls2and4. Thetegral U-shaped contact structurehaving the contact arms 2| and 22 of the U located within'therecessiloneachsideofthebosslinengagement with the walls thereof. Asshown by Fig. l, the body of the terminal member 2l is seated within agroove 23 formed in the outer wall of the base member and the terminalmember is held in position by means of a screw 2l threaded into the basemember. A plate of insulating material 25, such as sheet fiber. isdisposed between the head of the screw 24 and the terminal member 20 andserves to close the opening in the base member provided for insertion ofthe nxed contacts 2i and 22 within the recess ii. Cooperating with thefixed contact member 2|, is a movable contact blade 28, in this case theilrst movable contact member shown to the left in Fig. 4, which isformed of spring material and normally biased into engagement with thefixed contact. At' one end, the contact blade isv provided with acontact surface or button 2l cooperating with the correspondingxedcontact 2i and. at the other end, the contact member is reverselybent, as shown at 2l, and spot welded. or otherwise secured, to a leg ofa terminal member 22. The terminal member 20 is formed of flat stripstock with theleg disposed in a groove 2l formed in the wall of therecess, whileanother portion of the terminal is bent at an angle to thelegtoformaterminalhead forrecelving aterminal screw I2. The bent end ofthe terminal member rests upon a support ll extending from the side wallof the recess il. This means that the terminal member and contact blade22 may be placed in position within the switch housing simply byinserting the leg of the terminal member 2l in the corresponding groovein the housing so that the contact blade 2t is positioned within theleft-hand compartment of the recess il, in the manner shown by Fig. 4.

Another movable contact member 3l, whichmaybetermedthesecondcontactblade.islike wisedisposedwithintherecess ilontheside opposite the contact blade 2l and cooperates with the othernxed contact member 22. At one endtheccmtactbladelllsprovldedwithacontact surface or abutment 24 cooperatingwith the xed contact 22, and at the other end the contact blade is bent,as shown at 2i. and spot welded,

orotherwisesecured.toalegofaterminalmem ber 2l. The terminal is formedof flat strip stock and the leg is positioned within a groove II formedin the side wall of the housing. while another portion vof the terminalmember is bent atanangletothe'legtoformaterminalhead resting upon asupport 39 extending from the wall of the housing. A terminal screw 49coopcrates with the terminal for connecting an electric conductorthereto. The contact blade and terminal member are assembled in thehousing simply by inserting the leg 36` of the terminal member in thegroove 31 so that the bent end rests upon the supporting surface 39 andthe contact blade is positioned at the lower level of the recess, in themanner shown by Fig. 4.

The operating mechanism for the movable contact blades 26 and 33includes two cam disks 4I and 42 secured to a shaft 43 pivotally mountedin the casing. The cam 4I is provided with two flat surfaces and anarcuate surface for cooperation with each of the contact blades 26 and33, while the cam 42 is provided with an arcuate surface and a singledepression for cooperation with a projection 44 on the contact blade 26.The projection 44 is formed by lancing out the upper portion of thecontact blade, so that it engages the upper cam 42 only. It will bemanifest that the circular portions of the cams 4| and 42 hold therespective contact blades 26 and 33 in open position, while the fiatportions of the cam elements permit the contact blades to close. Thesequence in which the movable contact blades are opened and closed bythe cam members will be described later in connection with a descriptionof one use of the switch.

After the movable contact blades and cam members 4I and 42 have beenseated in position, the separating plate I9 is inserted in the recess toform a partition as shown in Figs. 2 and 3. The separating plate restsdirectly upon the cam member 42 and is of a configuration such that itfits snugly within the` recess II on each side of the bosses I and I6.In this position the separating disk insulates the contact structurethus far described from the contacts disposed at the upper level oftherecess.

The contact mechanism in the "upper portion of the recess includes aterminal member 45 having an integral fixed contact member 46. Theterminal is mounted on the upper portion of the boss I5 by means of ascrew 41 and the fixed contact extends at an angle to the terminalmember into the recess I I for cooperation with a contact button 49secured to a movable contact blade 59. The contact blade 50, in thiscase the third movable contact member, is bent at one end, as shown at5I, and is spot welded or otherwise connected. to the leg of theterminal member 29 in which position it is normally biased intoengagement with the fixed contact 46. This means that the contactblades'50 and 36 are electrically interconnected and lie one above theother but are separated by the insulating plate I9. Inasmuch as both ofthese contact blades are connected to the single terminal member 29, theblades are positioned simultaneously within the recess and theseparating plate I9 is then slipped into the recess between the contactblades in the manner described in the preceding paragraph. The movablecontact blade 50 is disposed in the left-hand portion of the recess, asshown in Fig. 2.

Another terminal member 52 having an integral ilxed contact 53 ismounted at the other end of the recess on the boss I6 by means of ascrew 54, and the contact 53 is bent at an angle at one end, as shown at58 and spot welded, or otherwise secured, to the leg of a terminalmember 59. 'I'he leg extends into a recess 66 in the l bent end forminga head portion resting on the to the terminal member for cooperationwith a supporting surface 39 and provided with a terminal 6I screw forsecuring an electrical conductor to the terminal member. In this mannerthe contact blade is positioned in the right-hand portion of the recess,as shown by Fig. 2, and is normally biased into engagement with thecontact 53.

'I'he second series of contact blades 59 and 51 are operated by two camelements 62 and 63 disposed one above the other within the upper levelof the recess II. The cam 62 is provided with three iiat contactengaging surfaces and a fourth arcuate portion for cooperation with eachof the contact blades 56 and 51 while the cam `member 63 is providedwith a circular portion having a recess therein for cooperation with aprojection 64 lanced from the upper portion of the contact blade 50. Thecam elements are likewise mounted on the shaft 43 and are rotatedsimultaneously with the cams 4I and 42 upon rotation of the shaft bymeans of a handle (not shown). The sequence of operation of the contactblades under rotation of the cams will be described later.

The recess II is closed by means of a plate 65 which extends completelyaround the upper wall I2 of the base member and provides a housing whichcompletely encloses the contact mechanism. The closure plate is providedwith a plurality of openings (not shown) for exposing the terminalscrews 32, 40 and 62, so that electrical conductors may be connected tothe movable contact mechanism.

Each of the terminal members 20, 45 and 52 is provided with conductorclamping means comprising an angularly shaped clamping plate 66 mountedon the respective terminals by means of a screw 61, and which is adaptedto clamp a conductor between itself and the terminal member. A bracket68 formed integrally with the closure plate 65 and having an openingtherein is provided as a ready means of mounting the switch upon asupporting plate.

In order' to assist in correctly positioning the cam-operating elementsfor operation of the switch, a positioning mechanism is located withinthe front part of the housing within the recess I3. having indentations16 corresponding to the number of positions of the switch mechanism,

-in this case four, which is mounted upon the shaft 43 for rotationtherewith. The indentations in the star wheel are engaged by rollers 1Irotatably supported on spaced levers 12 disposed in pairs on oppositesides of the star wheel. The levers 12 are pivotally supported on pins13, one end of each pin being located in a bearing recess 14 molded intothe partition I4 and the other end of each pin being supported in abearing 16 formed in a cover plate 16 closing the recess I3. In order tomaintain the rollers 1I releasably Within the depressions within thestar wheel a spring 11 is connected at each end to a pair of the leversby means of pins 19 disposed between the spaced levers. Upon rotation ofthe switchoperating mechanism by means of the shaft 43 the star wheelwill move the pivoted levers outwardly away from one another against theaction -of the spring 11 permitting the contact 'I'his mechanismincludes a star wheel 69.

rollers to roll into the next adjacent indentations in the star wheel.In this manner the operating positions of the cam elements are clearlydeilned by means oi the positioning mechanism. The positioning mechanismis held securely within the recess Il by means of the cover plate 1Iwhich is secured to the base member by screws 19 seated in openings Ilin the walls of the base member. By the construction described thepositioning mechanism is separated from the switch mechanism by thepartition I4.

In one use of the device shown by Figs. 5 to 8, inclusive, the switchisyconnected to control a two-part heater system such, for example. as anelectric range unit and the switch is connected to a three-line powersupply. In the diagrammatic showing of these iigures, the switch isconnected to give four heating values to the range unit. In connectingthe switch to the two-part heater system the terminal 2l is connected toone end of the part A of the two-part heater system, while the terminal59 is connected Ato one end of the other part B of the system.

The other ends of the parts A and B are placed in series and connectedtothe terminal Il. A threeline power supply designated N, L1 and In isconnected to the switch. To this end, the terminal 20 is electricallyconnected to the neutral line. the terminal 52 to the line Li and theterminal 45 to the line In. The diagrammatic showing of Figs. 5 to 8,inclusive, is looking at the back of the switch where the terminalmembers are located. This means that the switch handle appears to berotated counterclockwise whereas actually the switch is rotatedclockwise.

In the oiT position of the switch shown by Fig. 5, the camelements 4I,42, 82 and I3 are so positioned that each of the movable contact blades26, ll, lll and 81 is out of engagement with ythe corresponding nxedcontacts, so that no current nows through the two parts A and B oi' theheater system. By rotating the switch mechanism counterclockwise throughan angle of approximately 90 degrees, the switch is turned to highposition, as shown by Fig. 6. In this positiofn of the switch, currentows from the line L1 to the terminal member B2, through the fixedcontact Il, movable contact blade 61, terminal 59, and thence to one endof the unit B oi' the heater system. At the same time, current flows rfrom the line La to the terminal 4I, fixed contact 4I, movable contactblade l0, terminal 29 to one-end of the other unit A o! the heatersystem. Ihe current thus tiows through each of the parts' A and B of theheater system through a common line to the terminal 8l, movable contactblade iixed contact 22V, terminal member 20. and thence to the neutralline N. In this manner each part o! the heater system is placed inparallel across the power lines Li, La and N and a maximum output of'the heater system is attained.

In the medium" position o! the switch, shown by Fig. 7. the cam elementshave been rotated through an angle of approximately 90 from the showingoi Fig. 6 so that the movable contact blades 3l and S1 are in closedposition. Current from the power line L1 now nows through the terminalBI. iixed contact Il, movable contact blade 51. terminal Il, to one endof the unit B of the heater system. thence through the unit B to theterminal ..mnvable contact'blade 83. fixed contact 22, terminal memberIl to the neutral powerline N. Inthis manner one part of the heatersystem, i. e.. the heater unit B, is placed across the power lines L1and N.

To place the switch in the low position as shown in Fig. 8 the switchmechanism is rotated counterclockwise through an angle approximately 90degrees from the showing of Fig. '1, so that the cam elements close thecontact blades 28 and 51. In this position of the switch mechanismcurrent ilows from the line Li to the terminal member 52. iixed contactIl, movable contact blade il, terminal member 5l, to one end o! theheater unit B through the connection between the heater units to theheater unit A and thence to the terminal 2l, movable contact blade 26.fixed contact 2|. terminal member 2l to the neutral line N. This meansthat the two parts A and B ol the heater system are connected in seriesacross the power lines Li and N and a minimum output from the heatersystem is attained.

In order to place the switch mechanism in the on position it is rotatedthrough an angle oi' approximately 90 degrees counterclockwise from theshowing of Fig. 8.

While the switch has been shown as connected to a two-part heatersystem, it will be apparent to one skilled in the art that the switchmay be adapted i'or other uses. An advantage of the structure describedis that the switch may be rotated either clockwise or counterclockwiseto any one of the heat positions shown.

The arrangement oi' the stationary and movable contacts is such as toprovide a switch of compact construction and one in which the elementsare easily and quickly assembled` 'Ihe movable blades are mounted withinthe reces simply by slipping the terminal members in the groovesprovided in the wall of the recess. In this manner two of the contactblades are disposed in parallel relationship in the left-handcompartment of the recess while two others of the contact blades aredisposed in reversed parallel relationship in the right-handcompartment. This means that the pairs of blades are adequatelyseparated irom one another electrically by the cam members which arelocated centrally between the blades.

I claim:

1. In an electric switch, a base oi insulating material having a recesstherein, bosses extending into said recess from opposite walls thereof.

l a U-shaped terminal .member straddling one of said bosses and havingfixed contacts secured to each arm of the U on opposite sides of saidboss. movable contact blades in said recess engaging said iixed contactson opposite sides of said boss, another terminal member having a xedcontact mounted on said one boss above said U-ahaped terminal, a movablecontact blade co-operating with said last-mentioned fixed contact andbeing electrically connected toone of said mst-mentioned contact blades,a terminal having a nxed contact mounted on the other of said bosses andco-operating with still another'movable contact blade, and cam means ioroperating all oi'said movable contact blades in predetermined sequencefor co-operation with the nxed contacts to control a plurality ofelectric circuits connected to said switch. a

2. In an electric switch, a base of insulating material having a recesstherein, bosses extending into said recess from opposite walls thereof.a U-shaped terminal member having contacts on opposite sides of one oi'said boes, movable ccntact blades in said recess on opposite sides ofsaid one boss and ao-operating with a respective nxed boss, and cammeans within said recess between 10 said bosses for operating saidswitch contacts, said cam means including a plurality of cam memberseach co-operating with a respective pair of contact blades.

3. In an electric switch, a base having a recess therein, bossesextending into said recess from opposite walls thereof and forming twocompartments, cam operating means, two movable contact blades disposedin parallel relationship in one of said compartments on one side of saidcam means, a terminal connected to the ends of both of said bladeswhereby said blades are electrically interconnected, two movable contactblades disposed in reversed parallel relationship in the other of saidcompartments on the other side of said cam means, spaced terminalmembers, one being connected to each of said reversed contact blades andstationary contacts mounted on said bosses for co-operation with saidmovable contact blades.

DONALD G. KIMBALL.

